In this week's ShortList, we found out that their final scene together features a rather surprising cameo...

"I remember the final scene that he and I were shooting together," Paul reminisced. "It was this serious moment, I’m talking to him and I hear everyone laughing outside of the set and I’m like, “Why is everyone laughing?” Then I realise. He turns away from me and starts walking and I can see that his ass is out. Right in front of the camera."

So, there you go, the finale of one of TV's most brutal dramas is going to end on a bum note. Yeah, we went there.